More specifically, the infrared drier installation according to the present invention consists of, in a traditional way, the gas-heated infrared radiant elements, arranged one next to the other so as to form a set of at least one row stretching in the transversal direction of the web, more specifically over the entire width of the web.
It is known that the energy released by a gas-heated radiant element is released for nearly 50% as infrared radiation and for the other half as thermal energy of the combustion gases.
Cold air is carried along between the radiant elements and the web by the simple fact that the web passes by at high speed.
In a traditional way, cold air is amongst other things blown upstream the radiant elements and between the radiant elements in order to reduce the temperature of the combustion gases in the neighbourhood of these radiant elements. Consequently, the temperature of the combustion gases that come into contact with the surface of the passing web is thus limited at approximately 300° C., as a result of which the volume of these gases expands, thus supposing the use of powerful ventilators to suck these combustion gases and to recycle them, at least partially, to blow them on the surface of the passing web.
The energy released as infrared radiation is capable of penetrating in the passing web so as to be absorbed by the said web, with an excellent output of the transfer of this radiation energy.
On the contrary, the dilution of the combustion gases with cold air to reduce the temperature of the air and combustion gas mixture that comes into contact with the surface of the passing web considerably reduces the temperature difference between this mixture of air and combustion gas, on the one hand, and the surface of the passing web, on the other hand, thus resulting in a important reduction of the output of the transfer of thermal energy between the gaseous mixture and the passing web that has to be dried.